Locomotive



Ecc. 2l, 1937* R. M. OSTSRMANN ET AL 2,192,805

LOCONOTIVE 3 Sheets-Sheet 1 Filed OC'v '50: 1936 lNVENTOR Rana/,FM Osa-RAMA/Af. BY Aena/R WILL/AMS. 01%@Y ATTORNEY Dec. 2l, 1937.'

R M. OSTERMANN ET Al. 2,102.806

LOCOMOTIVE Filed bot. so, 193e l 5 sheets-sheet 2 INVENTOR RUOOLF M. 0s rele/WANN. ,9a7-NUR MILL/AMS,

Dec."21, 1937. l R. M. OSTERMANN ET A1. 2,102,806

l LOCOMOTIVE Filed Oct. 50, 1956 3 Sheets-Sheet 5 INVENTOR l @00o 1. F M. 0.5 TERMAA/M A R THl/E M//L L /A M5,

. Ww ATTORNEY Patented Dec. 21, 1937 UNITED STATES LOCOMOTIVE Rudolf M. Ostermann,

Kenilworth, Ill., and

Application October 30,

Claims.

This invention relates to locomotives and more specifically to the engines used on locomotives to convert the pressure energy ofthe steam into work.

It has been proposed in the past to use high pressure steamon a locomotive expansively in a turbine followed by a reciprocating engine. The reciprocating engine in these cases works down to pressures somewhat above atmosphere like the ordinary locomotive reciprocating engine in general use. The combination presents advantages but also some serious difficulties and it is the purpose of the present invention to remove the difiiculties and thereby to make the combination thoroughly practical. v

When such a combination is applied to a locomotive or similar tractive engine which has to be operated over a wide range of speeds and torques, the relative amount of expansion in the two stages must be adjusted in accordance with the conditions prevailing from moment to moment in order to avoid wasteful use of steam'. Otherwise the compounding will not result in a lower steam consumption than that of a turbine in which the entire expansion of the steam occurs in the turbine itself. The primary reason for resorting to this combination of a primary turbine with a secondary reciprocating engine instead of driving the locomotive with a single stage steam turbine is to prevent undue steam consumption during the period of starting and accelerating the train, during which periods the turbine eiiiciency is very unsatisfactory and results in wasteful operation. It will be clear that if a turbine is com.- 35 bined with a reciprocating engine in this way,

and the two are connected so that the steam is admitted from the boiler to the turbine through a hand controlled throttle, the turbine exhausting to the valves of the reciprocating engine, the

40 pressure in the valve chests in the engine will when the locomotive starts from a standstill build up. to boiler pressure, as the steam-does not expand in the turbine when the turbine is standing still. To prevent the engine under these condi- 4 tions slipping the wheels the dimensions of the cylinders of the reciprocating engine must be so small that the full boiler pressure will not produce more torque than can be resisted by the adhesion of the wheels to the track. When the locomotive with such a small cylinder speeds up and both the turbine and reciprocating engine increasetheir speed, it is not possible evenat sustained maximum running speeds to reduce the cut-off vsufficiently to allow the steam to expand 193e, serial No. 108,452

(ci. (so-65) far enough down in the reciprocating engine for economical operation.

To make such a combination of turbine and reciprocating engine suiciently Veconomical over a Wide range of speeds and loads, it is necessary to dimension the size of the cylinders of the reciprocating engine so that the full starting effort is obtained with a pressure intermediate between the boiler pressure and the desired exhaust pressure instead of admitting the steam at any time at full pressure to the reciprocating engine. For example, assuming a boiler pressure of 600 lbs. and an initial maximum steam temperature of 800 F., we have found that the best results can be obtained by designing the cylinders for about 240 lbs. pressure when the locomotive is started. This evidently necessitates introduction of some automatic device to vary the admission of steam to the turbine in such a way that the operating pressure at the admission of the reciprocating engine does not exceed certain values at starting and during acceleration. This necessity arises from the fact that a reciprocating engine Working over a range of practical cut-olfs and over a wide range of speeds has an entirely diiferent steam rate characteristic than a steam turbine working with constant admission pressure over the same range of speeds. A practical solution must include means for automatically varying the admission, pressure to the turbine during the period of starting and acceleration in order to adapt its steam rate characteristic to that of the reciprocating engine and thus to obtain maximum power from the combination with lowest steam consumption. Of course, the use of such an autol matic pressure control could be avoided if any excess steam admitted during starting or acceleration and which cannot be economically utilized in the reciprocating engine at such low speeds could be allowed to escape directly to the stack or to the atmosphere. This, however, is obviously inadmissible because of its wastefulness.

In developing such an automatically controlled steamv admission to the turbine, we have found it advisable to arrange the automatic mechanism so as to produce a back pressure on the turbine which is lowest at the shortest cut-offs and highest at the longest cut-offs of the reciprocating engine. In other words, we have found it advisable to lower the admission pressure to the reciprocating engine gradually as the cut-off for the reciprocating engine is shortened. Extremely short cut-offs of the reciprocating engine at the highest speeds of the locomotives are thereby avoided and the undesirably high pressure drop which such very short cut-offs would occasion through the customary valves as well as the concomitant excessive compression are thus avoided.

An illustrative form of the required means for effecting the desired operation is shown in the accompanying drawings. Fig. 1 of these drawings shows in lateral elevation a locomotive equipped with mechanism in accordance with our invention. Fig. 2 shows on an enlarged scale a sectional view of a portion of the required automatic mechanism. Fig. 3 shows the remaining part of such mechanism. Fig. 4 is an enlarged sectional View on line 4 4 of Fig. 2.

Referring first to Fig. 1, reference numeral I indicates the locomotive boiler, steam from which is delivered in the usual way to the superheater header 2 from which it flows through the steam pipe 3, Valve A, and pipe 8 to the turbine 4. The steam is iirst expanded in turbine 4 and then flows toi reciprocating engines 5 for further expansion. It will be understood that in accordance with ordinary practice there are two such reciprocating engines, one at each side of the locomotive, both connected tol the turbine exhaust. While we prefer the arrangement herein disclosed of one turbine exhausting to two reciprocating engines, it will be clear from a reading of the description that there might also be a separate turbine for each of the two reciprocating engines. The turbine is permanently or otherwise connected to the drivers 6 8 in any desired way, such for example as by means of the shaft l, pneumatically operated clutch 1a, and reduction gearing 1b, the last transmitting power from the turbine to the axle of one pair of the drivers, from which it is transmitted to the remaining drivers by the usual side rods 1c. The reciprocating engines 5 are connected to one pair of the drivers by the ordinary connecting rods 1d.

The automatic control mechanism for governing the pressure at which the steam is to be admitted to the turbine is housed in the casing A. This casing is connected to the turbine by the two pipes 8 and 9 and to the reciprocating engines by the pipe I8. In the form illustrated in the drawings, the throttle to control the steam flow from the boiler to the turbine is of the common multiple-valve form located at II in the superheater header 2. This throttle arrangement is well known and is shown in many prior patents, e. g. 1,662,955 granted to R. M. Brown on March 20, 1928. The throttle is operated by means of the rod I2 extending forward from the throttle lever I3 in the cab.

The control 4casing A and the controlling valve located in it are illustrated in section and on a larger scale in Fig. 2. Steam is delivered to this control through the pipe 3 when the throttle II is open and flows into the casing through the pressure reducing valve 22. It ows next through the passage I4 forming the inlet to the casing A. Within casing A is by-pass valve proper I 5 which is a. hollow piston valve. In its extreme right position, shown in the figure, this valve I5 opens port ia thereby putting pipe 8 into communication with passage I4 and pipe 3, at the same time shutting off passage I4 from ports I5b and I5c which are placed in communication with each other. In its other position, i. e. to the extreme left, valve I5 places ports I5a and I5b into communication with each other and port |50 into communication with pipe 3. Ports I5b and I5c communicate with pipes 9 and I0 respectively. With the by-pass valve I5 in the position shown, steam flows from passage I4 through pipe 8 to turbine li. rlhe turbine then exhaustsv the steam into the pipe 9 and this pipe carries the exhaust steam back to flow through the bypass valve A and to the pipe Il] which delivers such steam to the valve chests 5a of the two reciprocating engines. The reciprocating engines exhaust the steam directly in the usual way to the exhaust steam nozzle F.

The pressure reducing valve 22 is illustrated as a balanced double-seated valve. The valve-body 23 of this valve is actuated by a steam piston 25 which is subjected on its upper side to steam pressure from a source presently to be described, its downward movement being yieldably opposed by spring 26. Any leakage past piston 25 is Vented to atmosphere at 26a. The pressure above piston 25 is furnished by steam taken from the main steam pipe 3 by pipe 25a, this pipe having inserted in it a choke 28. The amount of pressure in pipe 25a on the outlet side of choke 28 is determined by the position of needle valve 32 controlling bleed port 2S. The needle valve 32 is actuated by a piston 38 working against a compression spring '3LY 33 is a port permitting any steam passed by needle valve 32 to escape to the atmosphere. When the piston 38' is forced up, it moves needle valve 32 to its closed position and interrupts the flow of steam from pipe 25ct to atmosphere at 33. Pressure above piston 25 will then build up, and this results in the piston being forced down in a direction to close pressure reducing valve 22. Piston 38 receives its actuating steam irom the annular passage I5d in by-pass valve casing A, this passage being in constant communication with the steam pipe I8. The upper end of spring 3! abuts against movable stop |09 about which more will be said below. For a given spring 3| and a given position of stop Ill9 valve 32 will be closed at a denite pressure in pipe I0. Ii this pressure drops valve 32 opens, pressure in 25a is released, and valve 22 opens to supply more steam to the turbine, thereby raising the pressure on the exhaust side of the turbine and. in pipe I0. Ii the pressure in pipe I8 becomes too high, valve 32 will be kept closed, pressure in 25a will rise and pressure reducing valve 22 will move toward its closed position,V cutting down the steam flow to the turbine and as a result the pressure of the exhaust from the turbine and in pipe I0.

It was pointed out above that in prior arrangements at starting and at very low speeds the steam pressure in pipe I8 will build up to full turbine inlet pressure. By our arrangement this is modied in a manner and for a reason now to be described. The boiler pressure in a typical case is, let us say, 600 lbs. per sq. in. The back pressure on the turbine, or the pressure of the steam going to the reciprocating engines, while operating at mid-position of the reverse lever is to be 150 lbs. per sq. in. This back pressure is to be increased as the cut-oir is lengthened up to 40% cut-off, but is to be limited at this point to 240 lbs. per sq. in., the engine cylinders being so lcomputed as to size that, tol avoid slipping the drivers, this pressure must not be exceeded. Similarly, for reverse position this pressure is not to be exceeded. The following mechanism is used to eifect this.

The reverse shaft |88 has mounted on it a cam ISI whose operative surface is engaged by the roller I82 mounted on one end of lever ID3. The lever is pivoted at I84 and has its other end connected by means of a pin, t`o rod |05. The oppcsite end of 'rod |05 is pivotally connected to one end ofV bell crank Illi, which is pivoted at |07 and Whose forked end |03V (see Fig. 4) bears on the upper side of stop |09 against which the upper end of spring 3| abuts.

'Ihe surface of cam |0| has two portions |0|a and ||b which place lever |06 into such position at reverse position, and forward position above a predetermined cut-oi position of the reverse lever, that the compression of spring 3| results in a pressure in pipe |0v of 240 lbs. persq. in. The cam has an intermediate surface portion |0|c engaged at forward positions of the reverse lever below said predetermined cut-off point, and resulting in a compression of spring 3| such that the steam pressure in pipe lliy is lower than 240 lbs. per sq. in. This portion of the operative cam surface between Bic and I0|a is preferably given such form that the resultant pressure in pipe l0 increases progressively from 150 lbs. per sq. in. at point of minimum cut-oir to 240 lbs. per sq. in. as the lever is moved from the shortest cutoff position to the longest cut-off position Vin either direction.

Steam turbines being capable of operating in one direction only a separate reverse turbine must be tted to such a locomotive unless arrangements are made to run the locomotive in its reverse direction with the reciprocating engine alone. We prefer this latter arrangement as it will save cost and weight and as .road locomotives, in which .the advantage of a primary turbine and a secondary reciprocating engine is particularly attractive, arenot required to run inthe reverse direction except at low speeds and for short distances. Mechanism is therefore provided by us to by-Dass the steam turbine completely when the locomotive is to run in reverse direction. At such times pressure uid, preferably compressed air from a compressed air reservoir 'Im (Fi-g. 1) is admitted from pipe 39a to the right hand end of air cylinder 38 (Fig. 2) through the 3-way valve 39. The position of the 3-way valve 39 is coordinated with the position of the reverse lever by means of arm 39h which actuates the valve and is itself actuated by the slide bearing 39e fixed to reverse rod 36. This 3-Way valve 39, depending upon its position, may admit pressure air to either the right or left hand side of the piston in cylinder 38, at thesame time opening to atmosphere the side of the piston to which air is not being admitted. It will do the former, that is admit compressed air to the right hand side of the piston, when the reverse lever is in reverse position, and will do the latter, that is admit air to the left hand side, in all "forward positions of the reverse lever.

When pressure air is admitted to the right side of the piston in cylinder 38, this piston will cause the by-pass valve i5 to shift to the left. The ports |5a and lh to pipes 8 and 0 are then cut oi from communication with pipes 3 and I0 and steam can ilow directly through the interior of the hollow by-pass valve I5 to pipe I@ and so to the reciprocating engine. The turbine is thus completely by-passed and the locomotive is driven by the reciprocating engine alone. The turbine either idles in an atmosphere of steam or, if it is desired, uncoupling means can be provided to disconnect it completely from the driving wheels. We show such uncoupling means at la which is a pneumatically operated clutch, the operating air being admitted through connection la', controlled by valve 1k in the cab.

When the reverse lever is in its forward position, the piston in cylinder 38 andthe by-pass valve 21 will assume the positions shown in the drawings. The fact that in reverse position oi the reverse lever the valve i5 is in such position that the turbine is by-passed does not affect the action of the reducing valve except as it may iniluence the extent to which the reducing valve must open to give the desired pressure in pipe idr-249 lbs. per sq. in. as a maximum in the illustrated case abo-ve, this being in response to the position of bell crank |06.

The action of the reducing valve will necessarily be somewhat sluggish and pressure in the pipe l0 leading to the reciprocating engine might at times rise beyond the desired point. To obviate this, We provide an emergency relief valve which controls a passage from pipe le to the exhaust. This relief valve is adjustable and is set so that the pressure in pipe l@ will not reach that at which the reciprocating engine might slip the wheels.

We provide a furtherrenement in this mechanism relating to the question of superheat. Where the initial steam temperatures are very high, the temperature of the steam arriving at the reciprocating engine steam chests may at times be too high for proper lubrication of the valves and pistons and for this reason` we provide means to desuperheat the steam at such times. One form of mechanism for this appears in Fig. 3. A vapor-filled thermostat 62 in pipe l0 is connected'by means of the capillary tube 63 to the bellows 64. This bellows operates a needle valve 65 controlling the steam flow from pipe l0 through pipe 66 to vent 6l to atmosphere. The position of needle valve 65 thus alters the pres.- sure on top of piston 60 which works against spring 69 and actuates the valve '|0. Water to this valve is supplied through pipe 'll and is sprayed into the steam at l2. This mechanism therefore results automatically in keeping the steam temperature at the desired point. The specific form of this desuperheater is immaterial and some other means for effecting the control may of course be used in lieu of the one shown.

What We claim is:

1. Ina locomotive having a boiler, driving wheels and reversing gear, the combination of a turbine and a reciprocating engine both operatively connected to said driving wheels, a iirst steam conduit to supply steam from the boiler to the turbine, a second conduit to convey steam exhausted from the turbine tothe reciprocating engine, a pressure reducing valve in said rst conduit acting in response to pressure variations in said second conduit to vary the admission of steam to the turbine and thereby to keep the pressure in said second conduitapproximately constant, and means to vary the point at which the pressure in said second conduit is held constant, said means acting in coordination with the reversing gear.

2. In a locomotive having a boiler, driving wheels and reversing gear, the combination oia turbine and a reciprocating engine both operatively connected to said driving wheels, a rst steam conduit to supply steam from the boiler to the turbine, a second conduit to convey steam exhausted from the turbine to the reciprocating engine, a pressure reducing valve in said first conduit acting in response to pressure variations in said second conduit to vary the admission of steam to the turbine and thereby to keep the pressure in said second conduit approximately constant, and means to vary the point at which the pressure in said second conduit is held constant, said means being so coordinated With the reversing gear as to raise the point of constant pressure in the second conduit as the cut-off for the reciprocating engine is shortened.

3. In a locomotive having a boiler, driving wheels and reversing gear, the combination of a turbine and a reciprocating engine both operatively connected to said driving Wheels, a rst steam conduit to supply steam from the boiler to the turbine, a second conduit to convey steam eX- hausted from the turbine to the reciprocating engine, a pressure reducing valve in said rst conduit acting in response to pressure variations in said second conduit to vary the admission of steam to the turbine and thereby to keep the pressure in and second conduit approximately constant, and means to vary the point at which the pressure in said second conduit is held constant, said means being so coordinated with the reversing gear as to make the point of constant pressure in said second conduit a predetermined minimum when the cut-oi for the reciprocating engine is longest, and to raise it progressively to a predetermined maximum as the cut-ofi is shortened.

4. In a locomotive having a boiler, driving wheels and reversing gear, the combination of a turbine and a reciprocating engine both operatively connected to said driving Wheels, a first steam conduit to supply steam from the boiler to the turbine, a second conduit to convey steam exhausted from the turbine to the reciprocating engine, a pressure reducing valve in said first con duit acting in response to pressure variations in said second conduit to vary the admission of steam to the turbine and thereby to keep the pressure in said second conduit approximately constant, and means to vary the point at which the pressure in said second conduit is held constant, said means comprising a resilient member the load on which determines the pressure at which the steam in said second conduit is held constant, and means to vary the load on said spring With variations in the setting of the reverse gear.

5. In a locomotive having a boiler, driving Wheels and reversing gear, the combination of a turbine and a reciprocating engine both operatively connected to said driving Wheels, a iirst steam conduit to supply steam from the boiler to the turbine, a second conduit to convey steam exhausted from the turbine to the reciprocating engine, a pressure reducing valve in said rst conduit acting in response to pressure variations in said second conduit to vary the admission of steam to the turbine and thereby to keep the pressure in said second conduit approximately constant, and means to vary the point at which the pressure in said second conduit is held constant, said means comprising a spring the load on which determines the pressure at Which the steam in said second conduit is held constant, and means to so progressively vary the load on the spring as the cut-oir for the reciprocating engine is shortened from longest to shortest cut-off that said constant pressure increases progressively from a predetermined minimum to a predetermined maximum.

RUDOLF1 M. OSTERMANN. ARTHUR WILLIAMS. 

